Packages

  • package root
    Definition Classes
    root
  • package io
    Definition Classes
    root
  • package dylemma
    Definition Classes
    io
  • package spac

    SPaC (short for "Streaming Parser Combinators") is a library for building stream consumers in a declarative style, specialized for tree-like data types like XML and JSON.

    SPaC (short for "Streaming Parser Combinators") is a library for building stream consumers in a declarative style, specialized for tree-like data types like XML and JSON.

    Many utilities for handling XML and JSON data involve parsing the entire "document" to some DOM model, then inspecting and transforming that model to extract information. The downside to these utilities is that when the document is very large, the DOM may not fit in memory. The workaround for this type of problem is to treat the document as a stream of "events", e.g. "StartElement" and "EndElement" for XML, or "StartObject" and "EndObject" for JSON. The downside to this workaround is that writing code to handle these streams can be complicated and error-prone, especially when the DOM is complicated.

    SPaC's goal is to drastically simplify the process of creating code to handle these streams.

    This package contains the "core" SPaC traits; Parser, Transformer, Splitter, and ContextMatcher.

    See the xml and json subpackages (provided by the xml-spac and json-spac libraries respectively) for specific utilities related to handling XML and JSON event streams.

    Definition Classes
    dylemma
  • package interop
    Definition Classes
    spac
  • package json

    This package provides extensions to the core "spac" library which allow for the handling of JSON data.

    This package provides extensions to the core "spac" library which allow for the handling of JSON data.

    Rather than creating explicit classes that extend Parser, Transformer, and Splitter, this package provides type aliases and implicit extensions. For example, JsonParser[A] is just a type alias for Parser[JsonEvent, A], and JsonParser is just a call to Parser[JsonEvent].

    Implicit JsonParsers are available for each of the JSON primitive types:

    • string
    • number (expressed as Int, Long, Float, or Double)
    • boolean
    • null (expressed as None.type)

    Helpers are available for parsing JSON arrays and objects:

    • JsonParser.listOf[A] to parse an array where each value is an A
    • JsonParser.objectOf[A] to parse an object where the value for each field an A
    • JsonParser.objectOfNullable[A] to parse an object where the value for each field is either null or an A, filtering out the nulls
    • JsonParser.fieldOf[A](fieldName) to parse a specific field from an object

    A DSL for creating json-specific ContextMatchers is provided to make it more convenient to call Splitter.json. For example:

    Splitter.json("foo" \ "bar").as[String].parseFirst

    Can be used to capture rootJson.foo.bar as a String in

    {
      "foo": {
        "bar": "hello"
      }
    }

    To "split" values inside arrays, index-related context matchers are available, e.g.

    Splitter.json("foo" \ anyIndex).as[Int].parseToList

    Can be used to capture each of the numbers in the "foo" array in

    {
      "foo": [1, 2, 3]
    }

    A note about JsonEvents in spac: JSON doesn't have any explicit markers for when a field ends, or when an array index starts or ends; those context changes are essentially inferred by the presence of some other event. For example, instead of a "field end" event, typically there will be either a new "field start" or a token representing the end of the current object. With spac, splitters and context matchers generally operate under the assumption that a "stack push" event (like a field start) will eventually be followed by a corresponding "stack pop" event (i.e. field end).

    To allow for this, these "inferred" events (FieldEnd, IndexStart, IndexEnd) are explicitly represented as JsonEvents in the stream being parsed. Keep this in mind when creating JSON ContextMatchers:

    • field-related matchers will match a stack like case ObjectStart :: FieldStart(_) :: _
    • index-related matchers will match a stack like case ArrayStart :: IndexStart(_) :: _
    Definition Classes
    spac
  • package xml

    This package provides extensions to the core "spac" library which allow for the handling of XML data.

    This package provides extensions to the core "spac" library which allow for the handling of XML data.

    Rather than creating explicit classes that extend Parser, Transformer, and Splitter, this package provides type aliases and implicit extensions. For example, XmlParser[A] is just a type alias for Parser[XmlEvent, A], and XmlParser is just a call to Parser[XmlEvent].

    Three main Parser methods are added to Parser[XmlEvent] via the XmlParserApplyOps implicit class:

    • XmlParser.forText - for capturing raw text
    • XmlParser.attr - for capturing mandatory attributes from elements
    • XmlParser.attrOpt - for capturing optional attributes from elements

    One main Splitter constructor method is added to Splitter via the XmlSplitterApplyOps implicit class:

    • Splitter.xml - for creating splitters based on an inspection of an "element stack"

    Three main Splitter member methods are added to Splitter[XmlEvent, C] via the XmlSplitterOps implicit class:

    • .attr - alias for .joinBy(XmlParser.attr(...))
    • .attrOpt - alias for .joinBy(XmlParser.attrOpt(...))
    • .text - alias for .joinBy(XmlParser.forText)

    A DSL for creating xml-specific ContextMatchers is provided to make it more convenient to call Splitter.xml. For example:

    Splitter.xml("things" \ "thing").attr("foo").parseToList

    Can be used to capture a list of the "foo" attributes in the <thing> elements in

    <things>
       <thing foo="hello" />
       <thing foo="Goodbye">
          <extra>junk</extra>
       </thing>
    </thing>
    Definition Classes
    spac
  • CallerPos
  • ContextChange
  • ContextLocation
  • ContextMatcher
  • ContextPop
  • ContextPush
  • ContextTrace
  • HasLocation
  • LowPriorityTypeReduceImplicits
  • Parser
  • ParserApplyWithBoundInput
  • Signal
  • SingleItemContextMatcher
  • Source
  • SpacException
  • SpacTraceElement
  • Splitter
  • SplitterApplyWithBoundInput
  • StackInterpretation
  • StackLike
  • Transformer
  • TransformerApplyWithBoundInput
  • TypeReduce
  • Unconsable

object Splitter

Source
Splitter.scala
Linear Supertypes
AnyRef, Any
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  1. Splitter
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Visibility
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Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. def apply[In]: SplitterApplyWithBoundInput[In]

    Convenience for creating Splitters with a specific In type; useful when type inference can figure out the other type parameters.

  5. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  6. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  7. def consecutiveMatches[In](p: (In) => Boolean): Splitter[In, Any]

    Create a Splitter that treats consecutive values matching the predicate p as substreams with no particular context value.

    Create a Splitter that treats consecutive values matching the predicate p as substreams with no particular context value. For example, given a matcher like i => i % 2 == 0, a stream like

    1 3 2 2 4 5 6 7 8 10 4 3 1

    could be treated as having three substreams:

    • 2 2 4
    • 6
    • 8 10 4
  8. def consecutiveMatches[In, Context](matcher: PartialFunction[In, Context]): Splitter[In, Context]

    Create a Splitter that treats consecutive matched values as substreams.

    Create a Splitter that treats consecutive matched values as substreams. For example, given a matcher like { case c if c.isLetter => c }, a stream like

    1 2 3 A B C 4 5 6 D 7 8 E F G H 9

    could be treated as having three substreams, where each substream's "context value" is the first letter in that group (because context is always defined by the beginning of the substream).

    • A B C with context 'A' (between the 3 and 4)
    • D with context 'D' (between the 6 and 7)
    • E F G H with context 'E' (between the 8 and 9)
    matcher

    A function defining which inputs count as a "match"

  9. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  10. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  11. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  12. def fromMatcher[In, Elem, C](matcher: ContextMatcher[Elem, C])(implicit S: StackLike[In, Elem], pos: CallerPos): Splitter[In, C]

    Create a splitter that keeps track of a "stack" which is pushed and popped by In events, starting a new substream when the given matcher matches the stack.

    Create a splitter that keeps track of a "stack" which is pushed and popped by In events, starting a new substream when the given matcher matches the stack.

    The primary use-case for this is when dealing with nestable data formats like XML or JSON, where a token could signify a push to the stack (e.g. an ElemStart event), and where you want to operate on events that occur within some specific stack of elements.

    For inputs that cause a push or pop to the stack, whether that input is included as "inside" the pushed context is up to the specific StackLike implementation.

  13. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  14. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  15. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  16. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  17. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  18. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  19. def splitOnMatch[In](f: (In) => Boolean): Splitter[In, Any]

    Create a splitter that starts a new substream every time the predicate function p returns true for an input.

    Create a splitter that starts a new substream every time the predicate function p returns true for an input. Any inputs passed through before the initial match will be discarded, but every event thereafter will be part of a substream. Context is ignored for substreams from this method - the context type is Any.

    For example, in a stream like 4 3 2 1 2 3 1 2 1 2 3 4, if our predicate was { _ == 1 }, then we'd have a new substream starting from each 1 input.

    • (new context) 1 2 3
    • (new context) 1 2
    • (new context) 1 2 3 4
    In

    The input type

    f

    The predicate function responsible for determining if a new context should start for an input.

    returns

    A splitter that starts a new substream for every input where p(input) == true

  20. def splitOnMatch[In, C](matcher: PartialFunction[In, C]): Splitter[In, C]

    Create a splitter that starts a new substream every time the matcher matches.

    Create a splitter that starts a new substream every time the matcher matches. Any events passed through before the initial match will be discarded, but every event thereafter will be part of a substream. The context for a substream is based on the value returned by the matcher for the event that caused that match.

    For example, in a stream like 4 3 2 1 2 3 1 2 1 2 3 4, if our matcher was { case 1 => "yay" }, then we'd have a new substream with context "yay" every time a 1 came through:

    • (new context: "yay") 1 2 3
    • (new context: "yay") 1 2
    • (new context: "yay") 1 2 3 4
    In

    The input type

    C

    The extracted context type

    matcher

    A PartialFunction that can extract a context value from inputs

    returns

    A splitter that starts a new substream for every input where matcher.isDefinedAt(input), with a context equal to matcher(input).

  21. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  22. def toString(): String
    Definition Classes
    AnyRef → Any
  23. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  24. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  25. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()

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Inherited from Any

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